This project will examine the effects of low-level chronic perinatal and acute lead exposure on the histological organization and electrophysiological function in a number of central nervous areas. Experiments will be conducted in brain grafts and brain slices in vivo, as well as in the intact animals. Other heavy metal toxicants, such as cadmium, mercury, and thallium, will also be examined. The techniques to be employed include histological and histochemical staining to localize various transmitter-containing cells and fibers, extracellular and intracellular recordings from single neurons, and local drug administration using multibarreled micropipettes. By determining any lead-induced alterations in histological and electrophysiological organization of brain areas, and comparing the vulnerability of developing versus mature central nervous system, we hope to define more precisely the potential hazards of low-level lead exposure. Moreover, the comparison of such changes in isolated versus intact central nervous sytems should provide insights into the mechanisms of any heavy metal-induced disturbances.